Spray type oil burner with air directing means



March 28, 1950 c. DEMUTH 2,502,210

SPRAY TYPE OIL B LJRNER WITH AIR DIRECTING MEANS Filed. July 15, 1946INVENTOR.

CHARLES DEMUTH.

zthe fuel pump side;

. Patented Mar. 28, 1950 UNITED STATES PATENT OFFICE SPRAY TYPE oILBURNER WITHAIR DIRECTING {MEANS Charles Demuth, MineolapN. Y.Application July 13, 1946;.SerialjNo. 683,482

/ This invention relates to burners for liquid luelpsueh'as oil burners,and theinvention is intended more especially for burners operatingshort-"and where it is desired to have a loose large-flame distributedas evenlyas possible over the-entire space, and of. course ascompletecombustion as possible is desired for fuel economy. These desirablecharacteristics require a large amount of air; and in attemptsheretofore made tosupplyextra. air two undesirable results have*beenprominent. First too long a tongue-like close or compact flame,with a resultant roar and =a .ten'dencyto blow out the flame; and second.:a flamewhose propagation is. completed. immediately adjacenttheburnernozzle and hence not in the 'desired position. substantially centrallyof the firebox or combustion chamber.

'An object of'this invention is toprovide an improved burner adaptedtosupplysuflicient air "for complete combustion without tending to blowout the flame and producing a relatively large, open, quiet or lazyflame propagatedzat a dis- :tancein frontoftthe burner nozzle.

-Another objectof the inventionis to provide a burner capable of facileadjustment and con- -trol'of' the air supply, liquid fuel supplyand'ignitionelectrodes.

Other-and further objectsand advantages'of "thekinvention will beapparentirom the follow- "ingdescription 'considered in-connection :with

the"accompanying'drawings, showing a present preferred form of theinvention, in which:

i Fig. 1 is a side elevational View looking from "Fig. 2 is a planviewof "the burner-shown in 1,'with'thetop coverremoved so as to'showcertain parts disposed withinthe casing; and

Fig."3*is a somewhat enlarged crossasectional viewsof the nozzle'endof-the burner shown in SE'i-gs. 1' and 2, taken on a horizontal planepassing *throughithe central axis of the nozzle as. shown in Fig. 1.Referring more particularlytoFigs; land 2; a

2 suchas by the motor shaft 4. A suitable blower rotor, A such as asquirrel cage motor 5 is con- -6 Claims; ((31.158-46) vemently-mounte'd"on. the shaft 4. The housing is preferably'provided witha-suitably-shaped par titionsuch as fi providinga bottom wall for therotor chamber and preferably spaced from the bottom 'ofthe housing toprovide a compartment for accommodating 'a control switch or othersuitable control mechanism'of the. character well known;-andairemovablerear door 1 provides access to this compartment. The housing I is alsoprovided with a :removable top panel or door 8 comprising the entire topand part of the back wall of the housing'and held in closed position bysuitable fasteners such as 9. The top, four sidewalls and partition 6provide the blower chamberfor therotor 5. The sidewalls of the :housingare preferably provided with outwardly extending flanges such as 10providing' feet for securing the housing'in position.

A cylindrical tubular member II is ri idly secured at its inner'endtothe front wall of housing I near-its top, .as by welding, auditsinterior is .in communication with theblower chamber through an openingprovided in the front wall. "A.slidably' adjustable panel I2 is-disposedover the-blower opening [20Lv (Fig. 1) in the side wall backrofthe pump'3, aroundthe shaft 4, to therebygprovide for regulating or Y adjustin'gtheisupply ofair. tothe burner. nozzle.

Theair tube=H a(Fig. 3) is-provided witha forward abruptly outwardlyflaring annular fiange'or lip 13-, "A second cylindrical tubular member:14, ofsubstantially smaller diameter than --.the-tube H, .is disposedconcentrically within the tube Hand rigidly fixed in place. as by a.plural-ity-of oircumferentially spaced radially extendingxstrutsssuchas15. The front end of the. inner air-ttube I4 is provided with a forwardabruptly-outwardly flaring annular flange or lip 15.preferably-terminating at its forward end beyond the lipl3 *andcooperatingly disposed therewith toprovide an-annu-lar outwardly flaringorificefor secondary air. The inner tube I 4 is :also provided with 2'8,forward abruptly inwardly flaringvannularflange or lip l1 preferablyterminating at .its forwardend beyond the lip l3 andprovidingarestrictedair orifice for primary air. The rearen'dofthe inner-tube I 4 is turnedinwardly to "PI'OVidBf-fli fr'ustro-conical portion I 8.spacedqmxiallyforwardly ofzthe housing I. :A secondary-. air damperring l9 is-slidably dis posed within-theouter; tube I I and isadjustably secured/in axial position byscrews such as 20 passing throughaxially :extending slots 2! in tuber. The ring [9 is .taperedto provideop- .positely disposed:frustroeconical sides the forward edge of whichcooperates with the end I8 of tube l 4 to provide a variable area throatwhen moved from the solid line to the dotted line position.

A liquid fuel pipe 22 extends along the axis of the tubes H and I4 andat its forward end is provided with a nozzle tip 23 having an atomizingorifice which is disposed adjacent and preferably somewhat forwardly ofthe primary air orifice provided by the forward edge of the lip [1. Therear end of pipe 22 passes over the top of the rotor (Figs. 2 and 1),spaced upwardly therefrom, and thence laterally outwardly through a slot24 formed in the casing wall and extending from its rear edge andterminating in a portion parallel with the burner nozzle axis and on thesame horizontal level. The end of pipe 22 which is disposed outside saidside wall is provided with an Lpipe fitting 25 having a hex portion 26disposed against the outside of said walls, straddling said slot, and acooperating lock nut 21 is threadingly engaged on said pipe and disposedadjacent the inside of said wall. When in operating position the pipe isrigidly locked to and supported from the side wall by the nuts 2B-21.This arrangement provides a facile means of adjusting the pipe andnozzle 23 in an axial direction; and also provides for removing the pipeand nozzle for cleaning or repair by disconnecting the compressioncoupling 28 (Fig. 1) to detach the flexible oil supply line 29. The pipe22 is preferably supported intermediate its rear and front end by asuitable bracket such as 30 which is 'slidingly engaged within the tubeII and is arranged to permit withdrawal of the pipe as aforesaid andwhich also serves as a mount for electrodes 3! whose forward firingpoints 32 are operatively disposed adjacent the nozzle 23.

Operation With the burner in operation, oil is supplied through thenozzle 23 and primary air through the air nozzle I! to produce a primarycombustible mixture fired by the electrode points 32. This produces aprimary flame somewhat of the form diagrammatically illustrated in Fig.1 and designated 33. By adjusting the intake air damper I2 the primaryflame may be adjusted to the desired extent which takes the usual formillustrated. Secondary air is supplied from the outer tube H and passesbetween the damper ring i9 and inner end I8 of the inner tube l4, andthence axially and divergently outwardly through the secondary airnozzle provided between the flanges l3!5 to provide an annularfrusto-conical secondary air stream whose longitudinal sectional form isapproximately illustrated diagrammatically in Fig. 1 and designated 34.This secondary air stream 34 surroundsor envelopes the primary flame 33and is spaced outwardly therefrom for a substantial distance axially infront of the burner tip. As viewed in operation it is readily seen thatthe primary flame continues its normal form for some distance in frontof the burner tip, and thereafter the final flame propagation takesplace by the gradual supply to the primary flame of secondary air fromthe stream 34 to produce a large looseor lazy flame and resultantsubstantially complete combustion. The distance in front of the tip,where the final complete combustion takes place, and the regulation ofthe volume of air required for complete combustion, may be regulated byaxially adjusting the ring damper I9. I have found that in theo'pen'position of ring IS the area of the'sec- 4 ondary air channelshould be large enough to supply about 25% of the total air supply.

Having thus described my invention with particularity with reference toa preferred embodiment thereof, and having referred to certainmodifications, it will be obvious to those skilled in the art, afterunderstanding my invention, that other changes and modifications may bemade therein without departing from the spirit and scope of theinvention, and I aim in the appended claims to cover such changes andmodifications as are within the scope of the invention.

What I claim is:

1. In a liquid fuel burner, the combination of an inner tube having aninwardly tapered orifice at its'forward extremity for supplying primaryair, a concentrically disposed outer tube providing jointly with saidinner tube an annular outwardly flaring orifice outlet mouth spacedoutwardly from and surrounding said first orifice in spaced relationthereto for supplying secondary air in a diverging axial direction, anda liquid fuel tube within said inner tube provided with a nozzle whoseorifice is disposed centrally of and adjacent to said primary airorifice, whereby upon combustion of said atomized liquid and primary airan axially directed primary flame is produced within an envelopingdiverging secondary air stream to thereby produce complete combustion ina zone spaced forwardly of said primary air nozzle and provide aresultant relatively large flame.

2. In a liquid fuel burner, the combination of an inner tube having arestricted orifice at its forward extremity for supplying a primary airstream, a concentrically disposed outer tube providing jointly with saidinner tube an annular outwardly flaring orifice spaced outwardly fromsaid first orifice for supplying secondary air in a diverging axialdirection, and a liquid fuel nozzle disposed centrally Within said innertube and terminating adjacent to said primary air orifice, whereby whenfuel is emitted into the centrally disposed primary air stream theresultant mixture is ignited and a first relatively dense axiallydirected primary flame is produced within and enveloped by the widerdiverging secondary air stream and thereafter complete combustion takesplace in a zone spaced forwardly of said primary air nozzle to provide arelatively large loose flame.

3. In a liquid fuel burner, the combination of an outer air tubeprovided with an outwardly flaring forward lip, an inner air tubecoaxially disposed Within said outer air tube and provided with aninwardly directed peripheral forward lip providing a restricted orificeand with an outwardly flaring forward lip cooperatively disposed withrespect to said outwardly flaring forward lip provided by said outer'airtube providing therewith an outwardly flaring annular orificesurrounding and spaced outwardly from said inner orifice, and a liquid.fuel tube extending in an axial direction within said inner tube andterminating at its forward end in a liquid nozzle whose orifice isdisposed substantially coaxially within said inner air tube adjacentsaid restricted orifice.

4. In a liquid fuel burner, the combination of an outer air tubeprovided with an outwardly flaring forward lip, an inner air tubecoaxially disposed Within said outer air tube and provided with aninwardly directed peripheral forward lip providing a restricted orificeand with an outwardly flaring forward lip and cooperatively dis- 76posed with respect to said outwardly flaring forward lip provided bysaid outer air tube providing therewith an outwardly flaring annularorifice surrounding and spaced outwardly from said inner orifice, saidinner tube being substantially shorter than said outer tube and havingan open rear end in communication with said outer tube whereby saidouter tube rearwardly of said inner tube provides a common conduit forsaid inner and outer orifices, and a liquid fuel tube extending in anaxial direction within said inner tube and terminating at its forwardend in a liquid nozzle whose orifice is disposed substantially coaxiallywithin said inner air tube rearwardly of said restricted orifice.

5. In a liquid fuel burner, the combination of a cylindrical outer airtube provided with an outwardly flaring forward lip, a cylindrical innerair tube coaxially disposed within said outer air tube and whose forwardend is bifurcated so as to present respectively inwardly and outwardlydiverging peripheral flanges, said inwardly extending flange providing arestricted orifice and said outwardly extending flange beingcooperatively disposed with respect to said outwardly flaring forwardlip provided by said outer air tube providing therewith an outwardlyflaring annular orifice surrounding and spaced outwardly from said innerorifice, said inner tube being substantially shorter than said outertube and having an open rear end in communication with said outer tubewhereby said outer tube rearwardly of said inner tube provides a commonconduit for said inner and outer orifices, and a liquid fuel tubeextending substantially axially within said inner tube and terminatingat its forward end in a liquid nozzle having an orifice spaced axiallyfrom said restricted air orifice.

6. In a liquid fuel burner, the combination of a first air nozzle, asecond air nozzle concentrically disposed surrounding said first airnozzle in spaced relation thereto, the outer extremities of said i firstand second air nozzles jointly provid ing an annular outwardly flaringorifice for pro: ducing an outwardly directed divergent annular airstream, said first air nozzle also providing an inwardly taperedrestricted orifice of a smaller diameter than and spaced inwardly fromsaid outwardly flaring orifice, and a liquid fuel nozzle disposedcentrally of said first air nozzle, whereby said liquid nozzle and firstair nozzle produce a relatively long flame of the combustion mixturespaced within an enveloping air stream sup plied by said annularoutwardly flaring orifice.

CHARLES DEMUTH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 120,680 Smith Nov. 4, 18711,817,470 Adams Aug. 4, 1931 1,933,701 Blythe Nov. 7, 1933 2,057,783Lattner Oct. 20, 1936 2,065,042 Berryman Dec. 22, 1936 2,078,021 Ro-dlerApr. 20, 1937 2,094,943 Gianola Oct. 5, 1937 2,133,485 Sherman et a1Oct. 18, 1938 2,163,915 Rief et al June 27, 1939 2,215,272 OBrien Sept.17, 1940 2,220,603 Hirtz et a1. Nov. 5, 1940 2,221,519 Jones et al Nov.12, 1940 2,308,439 Carroll Jan. 12, 1943 2,325,444 Vroom et a1 July 27,1943 2,344,519 Nagel Mar. 21, 1944 FOREIGN PATENTS Number Country Date105,155 Germany Jan. 10, 1927

